We found this circuit in a 1969 Mullard documentation. The same configuration appears elsewhere in this section. The control range is -2 dB to 19.5 dB at 30 Hz.
The circuit shown is from an old European publication. In it we have the way to activate a relay...
We found this circuit in a European publication from the 1990s. Transistors are still common types...
This circuit was found in an American documentation and can be added to common amplifiers of any...